Gosh, that must be really hard! With these things, you just need to give it time. Mum's cat, Milo, was really affectionate as a kitten. After a few distressing things happened, such as a few moves close together, she became withdrawn from us and took to hissing and spitting all the time. She also stopped taking fastidious care of herself. It took her over a year to settle down, and she is back to her old self, jumping on laps, sleeping on beds next to her humans and drooling all over them